On October 12 this year my Tesla Model Y electric SUV ran my house. Through a Sigenergy bidirectional charger in my garage at Noosa Heads, it supplied about 25 kWh to my home.
The battery in my driveway holds several times the energy of a typical home battery, and I have already paid for it, because it is part of my car.
That situation may not last. Owners around the world report that Tesla EV software from the 2026.38 branch, rolled out since October, cuts third-party discharge within minutes.
On the Tesla Motors Club forum, owners describe power stopping after about three minutes with a battery management alert, or after 15 to 20 minutes whatever the load.
The old workarounds no longer help. Drive Tesla Canada has reported the same. EleJoy, Tlyard and Sigenergy users are all affected, and Tlyard now warns customers that Tesla’s 2026 software detects “simulated charging” and may cut the power link.
And the release notes? “Security improvements” and <a href="https://www.notateslaapp.com/software-updates/version/2026.38.5.1/release-notes” rel=”nofollow noopener” target=”_blank”>minor fixes. Nothing about switching off a function that owners use every day.
No plan B for Australian owners
You might say: just use Tesla’s own system. Australian owners can’t. Tesla Australia has said its Powershare feature cannot be retrofitted to existing vehicles, and in Australia Powershare is vehicle-to-load only. Meanwhile, the same software branch delivered Powershare with Powerwall home backup to owners in the US and Canada.
So for every existing Tesla on Australian roads, third-party equipment is the only way to put the car to work for the home. If the software now blocks that equipment, the message is blunt: you can’t back up your home with our gear, and now you can’t do it with anyone else’s either.
The Tesla Australia owner’s manual tells owners: “Do not use the Battery as a stationary powernty page is narrower, excluding damage caused by third-party adaptors or chargers
Australian law is narrower again. The consumer guarantees cannot be signed away by a line in a manual. Apple learned this the hard way when the Federal Court ordered $9 million in penalties over the “Error 53” saga, after Apple told customers that third-party repairs voided their rights.
This is bigger than Tesla owners
Governments are paying households to install batteries and soak up the solar peak. Electric vehicles are the biggest batteries most households will ever own. Bidirectional charging is how that capacity reaches the home and, in time, the grid.
But that whole agenda now rests on goodwill. A single carmaker can switch off that capacity overnight, through a software update the owner cannot roll back, without telling anyone. Chargers bought in good faith become stranded. Competing suppliers lose access to the fleet. And the grid loses flexibility it badly needs.
The ACCC has already flagged “denying interoperability” as conduct that can distort competition in digital platform markets. A car that decides which charger it will talk to is a platform in all but name.
I am deferring Tesla updates on both my cars, which means I am also missing whatever genuine fixes they contain. I have asked Tesla in writing to hold updates until it confirms discharge will keep working. I have lodged a complaint with the ACCC asking it to look at competition and consumer law. I have also asked the Australian Electric Vehicle Association, as the voice of EV users, to back it.
Tesla may have a real safety or engineering reason. If so, it should say what it is, and show why a less restrictive answer would not work: certified partner equipment, discharge limits, or a published interface that charger makers can build to.
Three things. Carmakers should disclose functional changes in plain English before they ship. Owners should be free to use the bidirectional charger of their choice.
And regulators should set interoperability rules for vehicle discharge, just as Australia already requires rooftop inverters to follow common standards. If we can make inverters speak a common language, we can stop cars locking out the chargers they plug into.
My car still powers my house. It does so only because I have stopped it updating. No owner should have to choose between a safe, current car and a working home battery.
Mark Purcell is an electrical engineer and energy advocate based in Noosa Heads, Queensland. He owns two Teslas and a bidirectional DC charger, and has been a member of the Australian Electric Vehicle Association.
